A large number of actions have to be initiated and control signals produced in transmitting and receiving devices in mobile stations, the timings of which actions and control signals are correlated with a special pattern, which is specific for a mobile radio standard.
In recent years, a range of different standards have become established in the mobile radio field, which are being developed further or will be replaced by new standards in the future. Known examples of mobile radio standards are GSM (Global System for Mobile Communication), the 8 PSK (8-Phase Shift Keying) further development of GSM which is referred to as the EDGE (Enhanced Data Services for GSM Evolution) standard, as well as various standards based on the CDMA (Code Division Multiple Access) transmission method, such as UMTS (Universal Mobile Telecommunication System). A fourth-generation mobile radio standard is currently already being developed as MBS (Mobile Broad Band System).
The existence of different and competing standards has resulted in an increase in the requirements for mobile stations for mobile radio. Mobile stations are desirable which can support a plurality of mobile radio systems and standards at the same time. This is dependent on the mobile station being able to produce the various time patterns of the individual standards and being able to carry out suitable event control processes on this basis.
The transmission methods, such as CDMA and TDMA, for these two different mobile radio standards are based on different symbol clock frequencies, with the transmitted data normally being structured in transmission frames which each have a predetermined length. This structure and/or length of each transmission frame in a continuous signal sequence is predetermined and is identified by the mobile station. The mobile station has to align its time sequence control with this structure. Within this frame structure, there are often time periods in which no activities take place in the mobile station. Particularly in the times in which the mobile station is waiting for incoming calls, in the so-called paging mode, there are relatively long activity pauses in which the power consumption of the mobile station should be reduced to a minimum in order to achieve as long a standby time as possible with a power supply capacity that is as long as possible. It should thus be possible to stop or entirely switch off specific functional blocks within these activity pauses.
A prior art is known from German Laid-Open Specification DE 100 09 683 A1 in which as many units as possible, such as radio-frequency oscillators, counters or frequency dividers, are deactivated during activity pauses in order to reduce the power consumption in a mobile station which supports the GSM radio standard. During an activity pause, the time of the next activation of the mobile station is maintained by an audio-frequency oscillator. Furthermore, in response to an interrupt request which occurs during such an activity pause, the time period remaining to the next activation of the system is reduced in such a way that the reduced remaining time period is sufficient to prepare for the activation. In consequence, the standby state time is reduced in response to an interrupt request without losing the synchronization between the communication unit and its base station or main station in the process. The known method and the known mobile station have the disadvantage that only one radio standard is supported. The operation of a mobile station which supports a plurality of radio standards and in which the units of this mobile station which are associated with the different radio standards are deactivated in activity pauses cannot be achieved with the method and the mobile station which are known from the prior art.